This invention relates to a device for collecting oil and gas escaping from a seabottom wellhead blow-out, i.e. an uncontrolled eruption.
Blowouts from subsea wells usually contain oil, water and, initially, substantial quantities of gas. Upon reaching the surface the gas either burns or escapes to the atmosphere. However, even if there is a surface fire, most of the oil remains unburned and causes marine pollution. Several technologies have been developed for dealing with the surface oil to try to minimize pollution, with varying degrees of success.
Attempts at subsurface collection include an umbrella shaped fabric device used at the Santa Barbara blowout of about 10 years ago. This device was placed near the surface well after the blow-out had occured to collect rising oil. The oil was then pumped out of the top of the umbrella.
Another attempt at subsurface collection was made at the IXTOC well in Campeche Bay in 1979. In this case an inverted steel cone was installed above the well head after the blow-out with the cone below the ocean surface. The device was supported on a cantilever truss from a fixed platform on the ocean surface. Any oil and gas that were collected were conducted to the surface through a marine riser by means of the gas-lift process, i.e. the buoyancy of the gas provided the pumping force.
Other subsurface collection devices are shown in Miranda U.S. Pat. No. 3,643,741, where a hollow cone is secured to the ocean floor over a leaking fissure to collect leaking oil and conduct it to a storage tank; in Johnson et al. U.S. Pat. No. 4,283,159, where a dome is manuevered over a blow-out wellhead with a top valve left open to vent escaping gas as the dome is seated and sealed to collect escaping gas and oil; and in Cunningham U.S. Pat. No. 3,745,773, where a cone is positioned within a drilling frame above a wellhead to collect escaing gas and oil as drilling operations proceed.